Sorrier s...snake (6)

I believe the answer is:

sadder

'sorrier' is the definition.
('sad' can be similar in meaning to 'sorry')

's snake' is the wordplay.
'snake' becomes 'adder' (type of snake).
's'+'adder'='SADDER'

(Other definitions for sadder that I've seen before include "more blue" , "extra-blue?" , "More downcast" , "Unhappier" , "More unhappy (but hopefully 1 down)" .)

I've seen this clue in the Sydney Morning Herald.

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